HABITS OP TWO PARASITES OF BLOAV-FLIES. 219 



pupai'ium — with its posterior segments suiTOunded by the me- 

 conial discliai'ge, which di-ies rapidly. So that when the larval 

 skin bursts and recedes, the pupa (text-fig. 15), which does not 

 entirely free itself from the larval exuviiim, conseqiiently becomes 

 anchored to the meconium. This has been observed by emptying 

 the larval contents of a pujDaiium into a small glass tube. 



Text-fii>ure 15. 





% 



Pupa of -A^. brevicornis. Greatly magni tit d. Original. 



The duration of the pupal stage is variable. "This was 

 obtained in one case only. A larva pupated diu'ing the night of 



Sept. 17-18, 1908, The resulting adult female emerged 



at 10 a.m. Sept. 23, 1908, making a pupal stage of approximately 

 54 days. The avei'age length of this stage for the first spring 

 generation (17 cases) was 9 days (May 14-23, 1909)" (6). 

 Another observer states : — " The pupal stage occupies about 

 five days" (8). Those puppe observed by the writer ranged from 

 8-12 days. " When first formed, the pupfe are yellowish white, 

 the eyes garnet, with some duskiness at the caudal edges of 

 the abdominal segments soon afterwards ; the mandibles, legs, 

 antennee, and wing-pads gradually become dusky, and about 

 48 hours previous to eclosion, the head, thorax, and abdomen, in 

 succession, begin to show dai'k colour, the head and thorax 

 together becoming a deep black before the abdomen shows very 

 much colour, and then, after about 6 hours, the latter trims 

 gradually but rapidly black. About 20 hours before eclosion the 

 colour is jet-black, which just preceding emergence changes nearly 

 to the colour of the mature adult. At eclosion the adults are 

 fully coloured.'' (6.) 



The pupal exuvium, which is very stiflT, is a golden brown, and 

 does not recede as in the Braconid, but appears to be broken up 

 in parts; pieces which retain the outline of the antennae are 

 ■frequently found loose; similarl}^, pieces from the head and legs 

 can be found; the abdominal portion seems thinner, and is usually 

 attached to the apex of it when the insect emerges. 



